The present invention relates generally to a diffuser for slowing down the flow of a stream of liquid and more particularly to a specifically designed diffuser assembly for use in a dye laser amplifier of the type described in copending U.S. patent application Ser. No. 911,272, filed Sep. 22, 1986 and entitled DYE LASER AMPLIFIER INCLUDING A DYE CELL CONTAINED WITHIN A SUPPORT VESSEL and copending U.S. patent application Ser. No. 911,193, filed Sep. 22, 1986 and entitled DYE LASER AMPLIFIER INCLUDING A LOW TURBULENCE, STAGNATION-FREE DYE FLOW CONFIGURATION.
In each of the copending patent applications recited immediately above, both of which are incorporated herein by reference, a specifically configured dye laser amplifier is disclosed. This dye laser amplifier includes a dye cell assembly having an internal chamber in which a continuous replenished supply of dye solution of high velocity is excited by a first light beam in order to amplify the intensity of a second, different light beam passing through the dye. In an actual working embodiment, this apparatus operates at relatively high flow rates and the dye solution itself moves through the dye chamber at relatively high velocities. For example, the structure disclosed in the above-recited copending application is designed to operate at velocities greater than 170 feet/second, flow rates greater than 30 gallons/minute and pressures exceeding 150 psi. An apparatus of this type requires a diffuser at the outlet of its dye chamber in order to slow down the dye stream before the latter makes a turn within its internal plumbing. Because of the high flow rates and high velocities associated with the stream, the diffuser design is critical.
Heretofore, a typical diffuser assembly consisted of a generally tubular (rectangular cross section), axially extending diffuser body defining an axially extending passageway having a diverging cross section along its entire length, that is, from its upstream end to its downstream end. When such a design is utilized in a dye laser amplifier of the type contemplated herein, that is, one operated at relatively high flow rates and velocities, there is a tendency for the stream to separate from the internal wall of the diffuser as it flows through the latter. This results in a large pressure drop with its associated undesirable noise and vibration which is due to the high velocities and momentums associated with the flow of dye through the diffuser. As will be seen hereinafter, the present invention is directed to a particularly designed, uncomplicated and yet reliable diffuser, especially one suitable for large dye laser amplifiers, and specifically a diffuser through which the dye stream will flow without separating therefrom.